Well completion with single wire guidance system

Abstract

A system for guiding a well comprises a current source, a ground terminal electrically connected to the current source and grounded at the surface of the Earth, a reference wellbore comprising an intermediate casing (IC) that includes an IC electrical discontinuity and is electrically conductive between that the IC discontinuity and the IC bottom hole, a reference conductor electrically connected to the current source, a tubular that includes a tubular string electrical discontinuity (TSED), is electrically conductive between the TSED and the tubular bottom hole end (TBHE), and is inserted into the reference wellbore through the IC. Electrical connections exist between the tubular, the reference conductor, and the reference wellbore between the TSED and the TBHE, whereby current flowing through the reference conductor produces a magnetic field; magnetic sensors to sense the magnetic field and a guided wellbore is steered in response to the sensed magnetic field.

What is claimed is: 
     
       1. A system comprising:
 a current source; 
 a ground terminal, the ground terminal electrically connected to the current source, the ground terminal grounded at the surface of the Earth; 
 a reference wellbore comprising an intermediate casing, the intermediate casing extending from the surface of the Earth to a horizontal section of the reference wellbore, the intermediate casing further including an intermediate casing electrical discontinuity, the intermediate casing being electrically conductive between the intermediate casing electrical discontinuity and a bottom hole end of the intermediate casing; 
 a reference conductor, the reference conductor electrically connected to the current source, the reference conductor inserted into the reference wellbore; 
 a tubular, the tubular including a tubular string electrical discontinuity, the tubular inserted into the reference wellbore through the intermediate casing, the tubular having a tubular bottom hole end, and the tubular being electrically conductive between the tubular string electrical discontinuity and the tubular bottom hole end; 
 a first electrical connection between the tubular and the reference conductor between the tubular string electrical discontinuity and the tubular bottom hole end; 
 a second electrical connection between the tubular and the reference wellbore between the tubular string electrical discontinuity and the tubular bottom hole end, whereby current flowing through the reference conductor, the tubular, and the reference wellbore produces a reference magnetic field; and 
 magnetic sensors positioned to sense the reference magnetic field; and 
 at least one guided wellbore that is steered in response to the sensed reference magnetic field. 
 
     
     
       2. The system of  claim 1 , wherein the guided wellbore and the reference wellbore are substantially parallel and the magnetic sensors are located within the guided wellbore. 
     
     
       3. The system of  claim 1 , further comprising a plurality of guided wellbores each with a horizontal section, wherein each horizontal section is aligned substantially parallel with respect to the other horizontal sections and further wherein each of the horizontal sections is vertically aligned with other horizontal sections with respect to the surface of the Earth. 
     
     
       4. The system of  claim 1 , further comprising a plurality of guided wellbores each with a horizontal section, wherein each horizontal section is aligned substantially parallel with respect to the other horizontal sections and further wherein each of the horizontal sections is arranged vertically and horizontally with respect to the reference wellbore. 
     
     
       5. The system of  claim 1 , wherein the guided wellbore intercepts the reference wellbore. 
     
     
       6. The system of  claim 1 , wherein at least one of the magnetic sensors is located at the surface of the Earth. 
     
     
       7. The system of  claim 1 , wherein at least one of the magnetic sensors is located within the guided wellbore. 
     
     
       8. The system of  claim 1 , further comprising a liner, wherein the liner is electrically and mechanically connected to the intermediate casing, the liner extending from the intermediate casing to a bottom end of the reference wellbore and the tubular being within the liner. 
     
     
       9. The system of  claim 8 , wherein the liner further includes a liner electrical discontinuity. 
     
     
       10. The system of  claim 9 , wherein the liner electrical discontinuity is a gap sub or a non-conductive joint. 
     
     
       11. The system of  claim 10 , wherein the non-conductive joint is comprised of fiberglass, PEEK, or polyethylene. 
     
     
       12. The system of  claim 9 , further comprising a tubing string, the tubing string including a tubing string non-conductive section, wherein the tubing string is within the liner and wherein the reference conductor is within the tubing string. 
     
     
       13. The system of  claim 12 , wherein the tubing string is coiled tubing. 
     
     
       14. The system of  claim 13 , wherein the reference conductor has a grounded end, the grounded end electrically coupled to the reference wellbore between the tubular string electrical discontinuity and a tubing string bottom hole end. 
     
     
       15. The system of  claim 9 , wherein the electrically conductive tubular terminates in a landing bullnose. 
     
     
       16. The system of  claim 15 , wherein the liner further comprises a terminal joint between the tubing string non-conductive section and the tubing string bottom hole end and wherein the terminal joint electrically connects the reference conductor to the electrically conductive tubular. 
     
     
       17. The system of  claim 9 , wherein the liner terminates in a liner bullnose. 
     
     
       18. The system of  claim 17 , wherein the liner bullnose further comprises a landing ramp and wherein the landing ramp comprises slots and the terminal joint comprises colleted landing fingers, the colleted landing fingers being insertable into the slots.